"""
sum = 0
for i in range (1,11):
    sum += i
print(sum)
"""


"""
mark = int(input())
if mark >= 90:
    print("优")
elif 80 <= mark <90:
    print("良")
elif 70 <= mark < 80:
    print("中")
elif 60 <= mark < 70:
    print("及格")
elif mark < 60:
    print("不及格")
    """

"""
for i in range(1, 10):
    for j in range(1, i+1):
        print(f'{j}x{i}={i*j}\t', end='')
    print()
"""


"""a = 10
a /=2+3
print(a)
"""


"""
for i in range(101,201):
    flag = True
    for j in range(2,int(i ** 0.5) +1): # for j in range(2,i):
        if i%j == 0:
            flag = False
            break
    if flag:
        print(i,'是素数')
"""

"""
lines = int(input("输入要打印的行数:"))
for i in range(lines):
    for j in range(0, lines - i):
        print(end=" ")
    for k in range(2 * i + 1):
        print("*", end="")
    print()
"""

"""
lines = int(input("输入要打印的行数(奇数):"))
if lines % 2 == 0:
    print('请输入奇数')
    import sys
    sys.exit(0)
half_lines = lines // 2 + 1
# 打印上半
for i in range(half_lines):
    print(" " * (half_lines - i), end="")
    print("*" * (2 * i + 1))
# 打印下半
for i in range(half_lines - 1):
    print(" " * (i + 2), end="")
    print("*" * (lines - 2 - 2 * i))
"""

"""
lines = int(input("输入要打印的行数(奇数):"))
if lines % 2 == 0:
    print('请输入奇数')
    import sys
    sys.exit(0)
half_lines = lines // 2 + 1
# 打印上半
for i in range(half_lines):
    print(" " * (half_lines - i), end="")
    if i == 0:
        print("*")
    else:
        print("*", end="")
        print(" " * (2 * i - 1), end="")
        print("*")
# 打印下半
for i in range(half_lines - 1):
    print(" " * (i + 2), end="")
    if i == half_lines - 2:
        print("*")
    else:
        print("*", end="")
        print(" " * (lines - 4 - 2 * i), end="")
        print("*")
"""